Compression ring horizontal bracing system for building structures

ABSTRACT

This invention provides a construction method having at least one compression ring and its bracing and reinforcing tension plane installed at a targeted floor level, where the compression ring and the tension plane form a structural bracing system to protect a new building or a existing building from an external horizontal impact.

CROSS REFERENCE APPLICATION

[0001] This application claims priority from U.S. Provisional Patent Application No. 60/327,182 filed on Oct. 4, 2001.

BACKGROUND

[0002] Traditional tall buildings or tubular building structural systems utilize columns mainly to support typical vertical dead & live loads and horizontal wind & seismic loads. Nevertheless, this potential excessive-horizontal-impact problem becomes a reality after the Sep. 11, 2001 New York World Trade Center twin towers incident. Both twin towers, upon crashing by the hijacked airplanes from sideways, eventually collapsed. This tragedy reveals the inherited weakness of the traditional design for tall or tubular buildings especial for high rise buildings.

[0003] The invention, a compression ring horizontal bracing system, is designed to resolve the sudden excess horizontal impact problem a tall or tubular building structural systems have. This invention is applicable to new-construction or retrofit of existing buildings, and it provides improvement to deficiencies of tall buildings with tubular structural system. The material for the structural components could be steel, concrete, composite, combination or any material suitable to build these structural components. The bracing system could be provided at every level of the building floors or just at levels as required.

SUMMARY

[0004] With the compression ring horizontal bracing systems, building structures, especially tall buildings or tubular building structural systems, the building structure will be stiff enough to block the impact object from penetrating into the building and it also provides reliable bracings for the columns. Thus the building will be capable resisting external impact loads and preventing the building structure from progressive total collapse as what happened to the New York World Trade Center twin towers being crashed by the hijacked airplanes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005]FIG. 1 illustrates an example of installing compression ring at a circular or an elliptical floor.

[0006]FIG. 2 illustrates an example of installing compression circular or elliptical ring at the square or near square rectangular floor.

[0007]FIG. 3 illustrates an example of installing compression ring at the rectangular shape floor, where the rectangle has a significant ratio of longer side to shorter side.

DETAIL DESCRIPTION OF THE INVENTION

[0008] This invention will install the compression rings in the required building floors, where ties all or required number of exterior columns directly/indirectly rigidly to the compression ring(s) at those floors installed with compression rings. The number of exterior columns required to tie with the compression ring is depending on the individual building design. Next, arrange/modify the floor members in a way that the floor will act as a tension plane for the compression ring(s) on the floor. Finally, use the tension ring(s) as the tension plane block-out(s) for elevator/stairway with the support of the core column support framing where ties the required number of core columns rigidly with the tension ring(s) as well.

[0009] Thus, for buildings with tubular structural system, the new bracing system at different required levels is arranged in a way that the floors will become load transferable diaphragms to the building tube. The building structure is capable of resisting external impact loads and preventing from progressive total collapse. It is because the invention is tying all or sufficient number of columns on the floor together to resisting any external horizontal impact load, instead of one or few at a time. In addition, the new floor system itself, with its compression ring(s) and tension plane(s), is built strong enough for resisting the external impact object from penetrating through the wall of the tube of the tubular system. As the building equipped with this invention is hit by the external impact object, the compression ring will be in compression to resist the impact, and the floor plane will be trying to maintain the shape of the compression with act in tension. If pretension force would be introduced in the tension plane, the compression ring will be provided with increased stiffness.

[0010] Finally, the compression ring(s) together with tension plane(s) provide reliable bracings to the columns thus avoiding the vulnerability from the progressive total collapse. The floor plane should be designed in a way that when overloaded by vertical loads, it would fail locally but would not cause the failure of the compression/tension rings; therefore the rings would continue to be functioned as bracings to the columns.

[0011] Refer to FIG. 1, the building floor 10 of this example is either in circular, elliptical or any compression ring shape. As shown in FIG. 1 the exterior columns 30 are rigidly tied to the compression ring 25. Tension ring 15 block-out is located in the middle of the floor tension plane 35. To further increase the lateral stiffness of the building system the core columns 20 are all rigidly tied to the tension ring 35. This is a very efficient layout, since all the columns are directly connected to the compression ring 25 and tension ring 15. The compression ring 25 and tension ring 15 could be either circular or elliptical or a combination of circular and elliptical.

[0012] Refer to FIG. 2, the building floor 40 shown in FIG. 2 is a square or near square reinforced by circular or elliptical compression ring 45. Sufficient exterior columns must be rigidly tied with the compression ring. Again the tension ring 50 blocks out the core columns 55 area. Since the core columns 55 are much stronger columns, it is an advantage to provide rigid ties between the core columns 55 and the tension ring 50. If the compression rings 45/tension rings 50 and the tension plane 65 have tied sufficient columns and have provided sufficient stiffness to bounce off the exterior object which creates the exterior impact load, and there are sufficient exterior columns having reliable bracings provided by the floor system to avoid the progressive collapse, then not all of those exterior columns 60 at corner areas are necessarily to be tied rigidly to the compression ring.

[0013] As shown in FIG. 3, the rectangular shape floor 70 of this example has one side much bigger than the other. Provide 2 compression rings 85, one next to the other, and both rings 85 tie sufficient exterior columns 80 to the compression rings 85. The combination between the compression ring 85 and the tension plane 90 as a whole will provide sufficient stiffness to bounce off the exterior horizontal impact. Hide the weaker end, where columns have no rigid ties to compression ring, of the building at a location where it is not likely to receive any external impact load. Provide sufficient core columns in the weaker end and tie sufficient core columns 75 to the adjacent compression ring. Use the weaker end for elevator/stairway shafts.

[0014] Additional tension rings could be provided inside the compression ring as block-outs for safety escape stairways or elevators. 

I claim:
 1. A method for strengthening a building structure to resist horizontal impact, where the method comprising the steps of: installing at least one compression ring at a targeted story of the building; and constructing at lease one tension plane to brace and reinforce the compression ring at the targeted floor level.
 2. The method as claimed in claim 1, where installing at least one compression ring at a targeted story of the building further comprising the steps of: tying rigidly the compression ring with a plurality of exterior columns; and if needed, installing a plurality of columns to form the compression ring.
 3. The method as claimed in claim 1, where constructing at least one tension plane further comprising the steps of: constructing a tension plane to brace and reinforce the compression ring at the targeted level; and within the compression ring, installing at least one tension ring block-out that provides the continuity with the surrounding tension plane.
 4. The method as claimed in claim 1, where the compression ring is an elliptical shape.
 5. The method as claimed in claim 1, where the compression ring is a circular shape.
 6. The method as claimed in claim 1, where constructing tension plane is to reinforce the floor of the targeted floor level to form the tension plane.
 7. The method as claimed in claim 1, where constructing tension plane is to reinforce the ceiling of the targeted floor level to form the tension plane.
 8. The method as claimed in claim 1, where constructing tension plane(s) is to reinforce both the floor and/or the ceiling of the targeted story to form the tension planes.
 9. The method as claimed in claim 3, where the tension ring is an elliptical shape.
 10. The method as claimed in claim 3, where the tension ring is a circular shape. 11.The method as claimed in claim 3, where installing at least one tension ring is to install the tension ring around an elevator or an escape stairway and to provide the continuity of the tension plane for the block-out. 